Conducting polymer nanofibers for gas sensor

Nanostructured conducting polymers have been synthesized by dilute chemical polymerization method to obtain nanofibers of polyaniline (PANI). The aqueous solution of nanofibers shows a stable colloid dispersion, which is spread into an interdigitated electrode resulting a porous film for DC test; the film is also embed into a cavity element for RF analyzer. In the presence of specific chemical reagents, the conducting polymer materials will undergo conductivity changes to several orders of magnitude, which finally induce the change of film resistance and RF conductivity for sensing. The sensor response is strongly dependent upon the film morphology, porosity and humidity. The devices show a quick response (i.e., less than 60 s in 100 ppm concentration) and significant sensitive to various chemical gases (e.g., HCl and NH₃) at the concentrations of 10 - 1000 ppm. Such novel emerging chemoresistive RF technology will be opened the challenge for the remote wireless detection of explosives and other chemical agents.